WASHINGTON — U.S. Sen. Michael Bennet broke his hesitation on endorsing the balanced-budget amendment last week, joining nine other Senate Democrats — including Sen. Mark Udall — in pledging support for the idea.

The vague “sense of the Senate” resolution — it had no specific endorsements of any balanced-budget legislation, or specific budget-cutting ideas — made it a safe, yet symbolic, vote for Bennet.

Bennet says he doesn’t agree with most of the balanced-budget amendment versions out there — including one co-sponsored by his Senate colleague from Colorado, Udall. He does not agree with blunt across-the-board cuts — something that most versions require, according to economists.

In fact, Bennet’s version of a balanced-budget amendment looks less like something that would need to be ratified in the states and more like a simple congressional vote on President Barack Obama’s fiscal deficit reduction.

“I think there’s a lot of rhetoric around budgets,” Bennet said, noting that the current proposals are nowhere “remotely near the most effective way to deal with our budget, and if we write it the wrong way, we’ll create an even greater crisis.”

Last week’s Senate resolution, sponsored by Sen. Mike Lee, R-Utah, failed, even though 10 Democrats came over to support the idea. (Seven of the 10 Dems are up for re-election in 2012, but neither Bennet nor Udall has an election next year.)

On the campaign trail, Bennet deliberately distanced himself from endorsing a constitutional amendment to balance the budget — instead touting his Deficit Reduction Act, which would cap the federal deficit at 3 percent of gross domestic product after 2012.

And Bennet is working back rooms with a small handful of Republican and Democratic senators to draw up legislation that will likely pair the fiscal deficit reduction commission recommendations — which call for dramatic cuts to Social Security and defense — with a vote to raise the debt ceiling.

Udall, who also supports bringing the deficit reduction commission recommendations to a vote, is the lone Democrat co-sponsoring legislation that would change the U.S. Constitution to require that Congress balance the budget every year.

There are exceptions in Udall’s proposal — including a congressional override and in times of war.

Still, some economists believe this proposal would be nearly impossible to fulfill.

Michael Ettlinger, vice president for economic policy at the left-leaning Center for American Progress, said such an amendment would require, roughly, a 27 percent cut in all federal spending, except debt interest payments and Social Security. That is money from Medicare and Medicaid, defense, border security and transportation. It would also likely require tax increases.

“It’s pretty unrealistic,” Ettlinger said. “We’ve been harsh on people and we call them deficit peacocks instead of deficit hawks because they’re all show. I’m for a balanced budget, I’m for deficit reduction, but until you come up with the specifics, you’re blowing smoke. You’re not being honest with the public.”

Alan Viard, a scholar of tax and budget policy at the more right-leaning American Enterprise Institute, agreed.

“I don’t question the motives of people adopting this; if they do believe this is the way to do it, then they haven’t thought this through,” Viard said. “The people who are supporting this as a substitute to do something substantive, that is dishonorable.”

Udall says he has not seen balanced-budget numbers that would require 25 percent to 30 percent cuts in all spending, but “what we’re doing now is unrealistic,” he said.

“There is a parade of horribles like you’ve never seen,” Udall said, when asked whether he would support dramatic cuts to all federal programs. “This is why you hold hearings and work the balanced-budget amendment through the process and uncover those kinds of concerns.”

The idea of a constitutional balanced-budget amendment has been batted around since the 1970s, with ebbs and flows of popularity.

If 10 Senate Democrats — some politically vulnerable — jumped up to support the idea last week, then that’s proof the idea may be in its heyday right now, said former Republican U.S. Senate candidate Ken Buck.

“There is a lot of common ground,” said Buck, founder of Balance America, an organization pushing state legislatures to adopt a constitutional balanced-budget amendment to eventually send to Congress. “When the rubber meets the road is when it gets interesting. People are going to have to cut this program or that program and it may not be popular.”

It remains to be seen how far either Bennet or Udall will go in their pledge of support for deeply unpopular federal budget cuts.

Last summer, both voted for a so-called second stimulus package that would have added another $80 billion to the deficit. The measure did not pass.

When asked why the yes vote — even though it would raise the deficit — both Udall and Bennet staffers said their bosses wanted to extend unemployment insurance and help states with Medicaid costs.

Democrats Ed Perlmutter and Jared Polis have joined their Republican congressional colleagues in backing legislation that would allow the Bureau of Land Management to relocate it headquarters to the West, and possibly to Colorado.

Two conservative taxpayer advocacy groups filed suit Wednesday against new Denver campaign finance disclosure rules for issue advocacy committees that they say will violate the privacy rights of their donors.